[postgis-devel] [PostGIS] #1114: [raster] ST_Resample
PostGIS
trac at osgeo.org
Sat Jul 9 06:59:16 PDT 2011
#1114: [raster] ST_Resample
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Reporter: dustymugs | Owner: dustymugs
Type: task | Status: new
Priority: medium | Milestone: PostGIS Raster Future
Component: postgis raster | Version: trunk
Keywords: |
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Comment(by dustymugs):
Replying to [comment:13 pracine]:
\> Shoul I understand here that it is not possible to resample to a
rotated grid using GDAL?
>
> I agree that it is not clear what should be the desired behaviour with
the first series of variant when the raster is rotated... If the raster is
not rotated only changing the pixel size make sense (variant 1 and 3). You
want the upperleft corner to stay the same. But what if the raster is
rotated? I would solve this like this:
>
> 1) Take for granted that when no skewx and skewy are provided they are 0
and hence we lose the rotation if there was one.
>
> 2) Add a variant to the first series taking skewx ans skewy (like in the
second series) allowing to specify the new rotation if we want to keep
one.
>
> Do you want me to update the specs to reflect that?
No. You can resample to a rotated grid as you can specify the output
raster's geotransform, which gets used in the third stage of the
GDALCreateGenImgProjTransformer2 function.
http://gdal.org/gdal__alg_8h.html#94cd172f78dbc41d6f407d662914f2e3
I think the desired behavior is to maintain the skew of the input raster.
Only by specifying skew parameters should the resampled raster's skew
change.
Is it possible for you (or anyone else for that matter) to send me a small
set of skewed rasters? I could use landsat imagery but I'm looking for
something more manageable.
--
Ticket URL: <http://trac.osgeo.org/postgis/ticket/1114#comment:15>
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